Surface Treatment of Lignin Sourced Carbon Fibers: Principles, Processes, and Challenges

Abstract

In recent decades, carbon fibers (CFs) have attracted attention for their potential use as structural materials in sports, cars, aerospace, and bridges. Also, carbon fibers have been considered as the next-generation materials in the aviation industry, which have presented an enormous chance for the entire supply chain of carbon fibers. However, they are having inert surface and do not allow matrix material to make bonding with it. For this reason, the surface treatment of carbon fibers is one of the advised methods to develop adhesion between the two. So, good adhesion between the carbon fiber and the matrix must be supplied in order to maximize performance. In this chapter, we will introduce the brief overview of surface treatment for carbon fibers based on lignin showing superior performance and developing processability. Surface treatment, for lignin-based carbon fibers, is discussed primarily to identify the mechanism of interphase formation. The objective of this chapter is to review numerous methods used for the surface treatment of carbon fibers and to provide details on mechanical, chemical, and morphological changes happen in carbon fiber properties. It will also be presented that mainly used surface treatment methods are chemical, dry, and nano-surface treatments. Comparative study of these different methods helps in the selection of suitable surface treatment method in accordance with the requirement. Selecting appropriate surface-treatment methods might modify the carbon fiber surface through increasing the surface functional groups and surface area. Additionally, they can modify the carbon fiber surface with increasing the electro properties components on the surface for supplying the carbon fiber-matrix interactions.